The present invention discloses a high-capacity broadband access method, comprising: a broadband subscriber initiating an access request to an access unit; the access unit sending the subscriber authentication information to a control unit via a route switching unit; the control unit authenticating the subscriber with an internal or external authentication, authorization and accounting server, returning the authentication result to the access unit via the route switching unit, and sending the configuration information to the accessed subscriber; the route switching unit and the access unit accomplishing configuration of the subscriber information, allocating corresponding resource to the subscriber, and establishing a data channel for network access of the subscriber. The present invention also discloses a high-capacity broadband access device and a system thereof.